Generally, in the thermal power generation, combustible solids such as coal and oil shale, or combustible liquids such as heavy oil and waste oil are used as a fuel. One difficulty encountered in a conventional thermal power plant has been the problem of treating exhaust gas from an associated boiler in which the fuel is burned.
One reason for this is that the temperature of the exhaust gas has to be controlled at a stage prior to the dust removing stage since the exhaust gas is maintained usually at a relatively high temperature of about 300.degree. C. at the outlet of the boiler of the thermal electric power generating device. Another reason is that a desulfurizing device has to be provided for removing oxides of sulfur from the exhaust gas. A further reason is that it has been difficult to treat the ash contained in the exhaust gas. Particularly, where the desulfurizing device is installed, a difficulty has arisen from the fact that the overall construction cost of the thermal power plant is high. Another disadvantage has been that the amount of a desulfurizing agent to be used is large. A further disadvantage has been that it is difficult to treat the products formed by the reaction of the desulfurizing agent with the sulfur oxides, as is the case with the treatment of the ash in the exhaust gas. Particularly where coal is used as a fuel in the production of electric power, the problem of treating the ash and the sulfur oxides has become more and more serious.
It is an object of this invention to provide a method of using exhaust gas from an electric power generating device as a heat source and efficiently treating the ash contained in the exhaust gas.
Another object is to provide a method of efficiently treating sulfur oxides contained in the exhaust gas without the use of a special desulfurizing device.
A further object is to provide an apparatus for performing such methods.